Pesticide exposures among Hmong farmers in Thailand

Highland Hmong farmers in Thailand have abandoned shifting cultivation of subsistence crops and turned to chemical-intensive cultivation of non-narcotic permanent field cash crops. Three highland communities and Hmong in urban Chiang Mai were studied. Most rural study participants applied chemicals, primarily to control insects, weeds, and fungus, by backpack and machine sprays and by hand. Hmong women have less Thai language skill than men and less information concerning hazards of exposure or use of protective clothing. Most Hmong know of the health hazards, but many fail to use adequate protective clothing to prevent exposure. Screening showed 20-69% of 582 Hmong adults with risky or unsafe levels of cholinesterase inhibition, an indicator of exposure to organophosphate and carbamate pesticides. Exposure rates are as high among those who do not actually apply pesticides as among those who do, suggesting exposure by routes in addition to direct contact associated with application.